Vacuum pump



July 2, 1929. E. BANDOLY 1,719,747

VACUUM PUMP Filed April 9, 1926 2 Sheets-Sheet 1 E. BANDOLY V VACUUMPUMP July 2, 1929.

2 Sheets-Sheet Filed April 9, 1926 Passe-a July 2, 1929. UNITED- STATESl This invention relatesto an apparatus for pheric pressure forces oilthrough the pump.

Qtoward, or into, the vacuum system. The principal object of thisinvention 18 to provide a trap'forintercepting this fugitive oil.

Further. objects of the invention are to provide improved means foroperating the blades of theeccentric pumps, to produce a simple compactpiece of apparatus that can be readil manufactured at small cost andeasily hand ed in the laboratory, and to generally improve the characterof apparatus used for this p Se e; referredembodiment of the invention;is i lustrated in the accompanying drawin sin which Q ig. 1 is asectional view through an eccentric'pu'inp oil bath taken along the axisof thedr ving shaft; j i

Fig. 2 is a similar section taken on the line 22ofFig.1;j,; 7 s Fig.31's a section of the oiltrap taken on the line,3 "3 of Fig. 1;

Fig. 4 isan elevation of the inside face of the removable wall ofthe oilbath casing, and

Fig. 5Jis' a view similar to Fig. '1, illustrat ing}: construction of01]. trap and oil But these specific illustrations and correspondingspecific descriptions are used to make the invention clear and are notintended to require a limitation of the claims other than is madenecessary b the prior art.

The apparatus 'i lustrated includes an oil bath generally indicated by Aand an eccentric um nerally indicated by B and moun ed 1 3 bath.

The pump 'is of the eccentric ty including two umts, each composed of acy der 10, an eccentric rotor- 11,'drivenb a shaft 12 mounted concentricwith thecy 'nder and ablade 13 (Fig. 2) reciprocating in a slot 14 inthe cylinder wall and contacting with the outer surface of the rotor 11.The ends of the cylinders are closed by plates 15, 16 and 17.

The walls of the cylinders 10 are extended lateral] as indicated at 18,in the neighborhood 0 the slots 14, and the plates 15 and 16 havingcorresponding extensions tocover the side portions of the slots and makeworking contactwith the blades 13.

The plate 16 is equipped with ears 19 and tering the cylinder at adistance-not PATENT OFFICE.

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20, each having laterally extending pins 21 connected with one end of atensile spring 22, the other end of which is connected with one arm 23of the bell crank lever fulcrumed at 24 on the plate 16 and havinanother arm 25 resting upon the outer en of the correspondlng blade 13..This mechanism will serve to maintain the inner end of each blade inintlmate contact with the peripheral surface 26 of the correspondingrotor 11.

Each rotor has a relatively long zone of contact with. the innersurfaceof its cylinder, as -mdicated at 27 in Fig. 2. The periphery ofthe cylinder is equipped with an inlet passage 28 and an outlet passage29 engreater than the zone 27. vThe outlet passage is normally closed bya flap valve .30 and the inlet a passage is connected with the vessel tobe exis formed hol ow to provide a tra chamber 38 which is connecte withthe in et passage 28 at the bottom and equipped with a hose nipple 39 bywhich the ump may be nected with the vessel to exhausted.

In the form shown in Fig. l the bath is made of aluminum die casting andthe chamber 38 is provided with a lining shell of steel composed of acup-shaped element 40, a disk 41 closing its open si e, and areenforcing strut 42 bent back and forth as indicated in Fig. 3, andlying between the opposite sides of the chamber. A short piece of steeltubing 43 extends from the inner side of the chamber to'the outer faceof the late 15. A sealing cup 44 has a shouldere neck 45 extendingthrough the lining and the aluminum and threaded to receive the hosenipple 39.

' In practice, the reenforcement is welded at the molding die and aboutwhich the jacket of aluminum, zinc, alloy, or other light metal Iplished in the following manner.

Plug the tubing; screw the cups 44 onto the nipples of a manifoldconnected with a vacuum pump; exhaust the trap chambers and submerge thecastings in a sealing material normally solid, but temporarily renderedliquid, such as, for example, apan; continue the submerging until theatmospheric pressure has had an ample opportunity to force the japaninto the minute pores; remove and bake to solidify the japan; immerseagainv without exhausting and bake the scond time. The lower portion ofthe removable wall 31 is thin and solid as indicated at 46, and

- equipped with a marginal flange 47 terminatmg in alignment with theinner face of the upper portion, this face 48 and the corresponding faceof the flange 47 areground to cooperate with the ground face 49 of theplate 15 to form a proper joint.

The plate 15 is extended beyond the margins of the cylinder 10, asindicated at 50, (Fig: 2) and drilled and -tapped-to receive studs 51 bywhich the pump is secured to the wall 31, the latter being thickened at52and 53 and drilled and tapped to receive the studs.

The removable wall is also thickened and drilled at 54 to receive studswhich thread into tapped openings in the body of the bath and secure theremovable wall in place.

The lowerportion 46 of the wall 31 is provided with a boss 55 alignedwith a brass insert 56 which, together with the land 57 and packing 58,forms a stufiing box ior the shaft 12.

When the bath is made of cast iron the re-.

movable wall 60 (Fig. 5) is formed with a trap chamber 61 without anylining, corresponding to that shown in F i s. 1 and 3. Any pores in thewalls of this c amber may be sealed by the procedure described above.-

I claim as my invention:

1. In apparatus of the class described, the combination of an oil bathincluding a cas' ing, a pump within the bath and an inlet passageleading from the pump through the easing and adapted to be connectedwith the vessel to be exhausted, said inlet passage being enlargedwithin the casing to form an oil trap.

2. In apparatus of the class described, the.

nection between the chamber and the vessel to be exhausted- 3,

3. In apparatus of, thelclass d;escribed,"the combination of a pumpincluding a cylinder, an eccentric rotor in the cylinder, an oil bathfor the pump including a casing having a wall formedhollow above therotor, a passage connecting the cylinder with thehollow of the wall andmeans for connecting the hol- "low of the wall with the vessel" to beex- -hausted. i

4. In apparatus of the class describcd,'the combination of a pumpincluding a cylinder, a rotor within the cylinder, a shaft driving therotor, an oil bath for the pump including a wall having a chamber formedin its upper portion, an inlet passage for the pump connected with thechamber in the wall, a stuffing box for the shaft in the wall below thechamber and an oilcavity in the wall'sufrounding the stuflingbox andcommunicating with the bathi" 5. In an oil bath for pun-1 m casing madein two parts, the first part including a bottom and walls for-three sides,'the second part including a waltfo'r the remaining side and adaptedto be secured to the first .part, said second part having an oil trap.formed in its upper portion'and adapted to. be connected with the pumpand with' the vessel to be exhausted. p,

6. In an oil sealed exhaust pump, an oil trap comprising a shellofwrought metal and a sheet of cast metal enclosing the shell and in thecondition of having been cast thereon.

7. In'an oil sealed exhaust pump, an oil trap including a shell ofsteeland an enclosing casing of light metal cast about the shell.

8. An oil sealed exhaust pump, comprising an aluminum die casting havinga hollow therein and a lining of non porous wrought metal for saidhollow. I

9. An oil sealed exhaust pump,'comprising a hollow light metal diecasting lined with ferrous wrought metal. 7

10. In a pump of the characterdescribed, the combination of'acylinder,.an eccentric rotor mounted therein, a blade slidable throughthe wall of the cylinder and making contact with the surface of therotor, a pivoted lever resting on the outer end of the blade and ahelical tension spring spaced from the pivot of the lever and constantlyurging it against the blade.-

11. In a pump of the character described, the combination of a cylinder,an eccentric rotor mounted therein, a blade slidable' through the wallof the cylinder and means tor holding the inner end of the blade incontact with the eccentric surface of the rotor, comprising a bent leverhaving one arm opcratively connected with the outer end. of the bladeand a helical tensionspring spaced from the bend of the lever andconstantly acting upon the other arm.

, 12. In a pump of the class described, the combination of a cylinder,an eccentric rotor mounted therein, a blade slidably mounted in the wallof the cylinder, and means for urging the blade into contact with theeccentric surface of the rotor comprising a tension spring, a bell cranklever having one arm connected with the spring and the other armoperatively connected with the plate.

13. In a device of the class described, a wall section comprising ahollow upper portion and a thin flat lower portion in line with theouter wall of the upper portion and having.

a marginal flange extending inwardly to a point approximately in linewith the inner wall of the hollow portion, and a boss propectinginwardly from the flat portion for receiving a stufl'ing box.

14. In an oil bath for pumps of the class described, a casting forming awall thereof and comprisng a thin Wall below encircled by an inwardlyprojecting marginal flange arid a double wall above providing a trap for01 15. In an appaartus of the class described, the combination of an'oil bath including a casing having one removable side wall, a pumpattached to the removable side wall and located in the bath, said pumphaving an inlet passage extending through the removable side wall andbeing enlarged above the pump to form an oil trap.

16. In apparatus of the class described, an oil trap comprising a shellof non-porous metal, and a casing of porous metal including the shelland in the condition of having been cast about the same.

17. In an apparatus of the class described, an oil trap formed of metalhaving its pores occupied by material impervious to fluids.

18. An apparatus of the class described, the combinatlon of an oil bath,a pump therein having an inlet passage and an oil trap for the inletpassage including a hollow casing of metal having its pores occupied bymaterial impervious to flulds.

In testinmony whereof I aflix my signature.

ERICH BANDOLY.

